Businesses under the metalworking industry can opt for a wide array of processes to ensure that their products can attain notable properties and characteristics. One of these processes is hardening.

Hardening is a metalworking process that can increase the hardness of metal products. This process is normally conducted by exposing the products to a specific amount of heat before proceeding with controlled cooling. The main purpose of increasing the metal products’ hardness is to ensure that they obtain higher resistance to plastic deformation.

Two types of hardening processes that can be utilised in working with metal products are case hardening and induction hardening.

Case Hardening

Case hardening is a hardening process that exposes metal workpieces to carburisation. This process is done by heating the workpieces to over 880°C so they can become austenitic. Subsequently, a carbon-emitting medium will transfer the coal to the workpieces so they can receive more carbon without affecting their carbon density. The transfer of carbon, which is known as carburisation, enables the hardening of the workpieces. Once the workpieces have completed the carburisation process, they will be annealed to restore their much-needed plasticity.

The primary purpose of case hardening is to increase their surface hardness and vibration resistance while retaining their ductile and elastic core microstructure. This process can ensure that metal products can boast increased lifetime, enhanced wear-resistance, and improved flexibility and weldability, making them useful under stressful conditions. Some notable applications of case hardening include the production of cooking utensils and the reinforcement of metal girders.

Induction Hardening

Induction hardening, on the other hand, entails the heat treating, quenching, and annealing of workpieces separately. The parts are exposed to an electromagnetic alternating field through a current-carrying coil. The field used for the induction hardening can produce eddy currents, which are known for flowing in the opposite direction to the currents that generate heat. Once the parts are placed inside the coil, they are then heated within or above their transformation temperatures before exposing them to the quenching process. This specific process is monitored by a control system to yield great results.

The primary purpose of induction hardening is to increase the mechanical properties of metal workpieces. One of the advantages of induction hardening is that it can increase the wear resistance of the workpieces. The workpieces are likewise expected to gain increased strength and fatigue life once induction hardening is applied. Workpieces can also be tempered even after the induction hardening process so their hardness level can be adjusted on the fly.

Both case hardening and induction hardening can be beneficial for industries that want high-quality metal workpieces. To know more about these processes, you can contact us at Alpha Detroit Heat Treatment. We provide a wide range of services for all your heat treatment needs. Our expertise allows us to suggest the most appropriate process for your heat treatment requirements.

Metal workpieces often undergo numerous processes to obtain substantial changes in their properties. One of these processes is the heat treatment process.

Heat treatment is a term used to describe activities that can alter the physical properties of a metal workpiece. This specific process typically involves heating or cooling in introducing changes to the involved part or component. Some properties that are affected by the heat treatment process include hardness, ductility, strength, toughness, and resistance to elements.

One great thing about the heat treatment process is that it can be done in numerous ways. It can even be done in various locations, ensuring that a workpiece can obtain its needed changes.

Issues with Heat-Treating Metal Workpieces

Before its processing, a metal workpiece is often exposed to various surrounding elements such as oxygen, carbon dioxide, and moisture. And with prolonged exposure to these elements, the metal workpiece may obtain changes and reactions, especially if it is processed with intense heat.

Now, to minimise undesirable reactions, professionals would often eliminate the source of the reactive elements from the heat-treating environment. One way of doing this is to replace the air in the heat-treating chamber with nitrogen, argon, or other gas combinations. Another way would be the exposure of the metal workpiece in a non-reactive molten salt bath. These processes may deter most of the undesirable reactions from the elements, but the workpiece would still contain low levels of impurities.

Vacuum Heat Treatment is the Key Solution

Vacuum heat treatment, fortunately, can remove most of the reactive elements from the heat-treating environment or heat-treating chamber. With the help of a vacuum pumping system, it can get rid of most air elements inside the heat-treating chamber that cause undesirable reactions and discolouration to the workpiece. Sometimes, an oil diffusion pump is installed alongside the pump system so that it can further eliminate elements and allow more sensitive metal workpieces to be heat treated.

The furnaces used for the vacuum heat treatment, however, can only be effective if they are maintained regularly. Without proper maintenance, they might develop some leaks, which can only lead to contamination during the heat treatment process.

The Processes of Vacuum Heat Treatment

Vacuum heat treatment starts with the positioning of the workpieces in a special chamber. With a vacuum pumping system and other related components, the elements inside the chamber will be removed and replaced with argon gas or other similar elements. Once these steps are done, the chamber will be subsequently heated up to as much as 1,300 degrees Celsius before lowering it for some time. The entire cycle of the vacuum heat treatment may take three hours to one day, depending on the needed material.

A fully maintained vacuum heat treatment furnace can easily produce workpieces with boosted strength and improved thermal efficiency. It can likewise avoid oxidation, decarburisation, and carburisation.

To know more about this process, you can call us at Alpha Detroit Heat Treatment.

Sources:

Benefits of vacuum heat treatment. Jones Metal Products. (2020, June 11). https://www.jmpforming.com/blog/vacuum-heat-treating/benefits-of-vacuum-heat-treatment.htm.

MetalTek International. (2021, June 2). Heat Treatment | Metal Processing. MetalTek. https://www.metaltek.com/capabilities/heat-treatment/

VAC AERO International. (2019, May 15). Why Heat Treat in a Vacuum?Vacaero. https://vacaero.com/information-resources/vac-aero-training/650-why-heat-treat-in-a-vacuum.html